import React, { Component } from 'react';
// store,用于获取reducer保存的状态
import store from '../../redux/store'

export default class Count extends Component {
  
    // componentDidMount() {
    //     // 检测redux中的状态变化，只要变化，就调用render
    //     store.subscribe(()=>{
    //         // this.forceUpdate() // 强制刷新
    //         this.setState({})
    //     })
    // }

    increment = () => {
        // 加法
        const {value} = this.selectNumber
        store.dispatch({
            type: 'increment',
            data: value * 1
        })
    }
    decrement = () => {
        // 减法
        const {value} = this.selectNumber
        store.dispatch({
            type: 'decrement',
            data: value * 1
        })
    }
    incrementIfOdd = () => {
        // 奇数加
        const {value} = this.selectNumber
        const count = store.getState()
        if (count % 2 !== 0){
            store.dispatch({
                type: 'increment',
                data: value * 1
            })
        }
    }
    incrementAsync = () => {
        // 异步加
        const {value} = this.selectNumber
        // const {count} = store.getState()
        setTimeout(()=>{
            store.dispatch({
                type: 'increment',
                data: value * 1
            })
        }, 500)
    }
  
    render() {
        return (
            <div>
                <h1>当前求和为：{store.getState()}</h1>
                <select ref={c => this.selectNumber = c}>
                    <option value="1">1</option>
                    <option value="2">2</option>
                    <option value="3">3</option>
                    <option value="4">4</option>
                </select>&nbsp;
                <button onClick={this.increment}>+</button>&nbsp;
                <button onClick={this.decrement}>-</button>&nbsp;
                <button onClick={this.incrementIfOdd}>当前求和为奇数再加</button>&nbsp;
                <button onClick={this.incrementAsync}>异步加</button>
            </div>
        );
  }
}
